asm-generic/io.h: move ioremap_nocache/ioremap_uc/ioremap_wc/ioremap_wt out of ifndef CONFIG_MMU

It allows some architectures to use this generic macro instead of
defining theirs.

sparc: io: To use the define of ioremap_[nocache|wc|wb] in asm-generic/io.h
It will move the ioremap_nocache out of the CONFIG_MMU ifdef. This means that
in order to suppress re-definition errors we need to remove the #define
in arch/sparc/include/asm/io_32.h. Also, the change adds a prototype for
ioremap where size is size_t and offset is phys_addr_t so fix that as well.

Signed-off-by: Greentime Hu <greentime@andestech.com>
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index b4531e3..7c6a39e 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -852,7 +852,16 @@ static inline void __iomem *__ioremap(phys_addr_t offset, size_t size,
 }
 #endif
 
+#ifndef iounmap
+#define iounmap iounmap
+
+static inline void iounmap(void __iomem *addr)
+{
+}
+#endif
+#endif /* CONFIG_MMU */
 #ifndef ioremap_nocache
+void __iomem *ioremap(phys_addr_t phys_addr, size_t size);
 #define ioremap_nocache ioremap_nocache
 static inline void __iomem *ioremap_nocache(phys_addr_t offset, size_t size)
 {
@@ -884,15 +893,6 @@ static inline void __iomem *ioremap_wt(phys_addr_t offset, size_t size)
 }
 #endif
 
-#ifndef iounmap
-#define iounmap iounmap
-
-static inline void iounmap(void __iomem *addr)
-{
-}
-#endif
-#endif /* CONFIG_MMU */
-
 #ifdef CONFIG_HAS_IOPORT_MAP
 #ifndef CONFIG_GENERIC_IOMAP
 #ifndef ioport_map